As a detection method of lung adenocarcinoma, a method has been known in which human lung adenocarcinoma is detected by measuring it using antibodies for carcinoembryonic antigen (CEA) and sialyl SSEA-1 (SLX) known as tumor markers. However, in the diagnostic method which detects these tumor markers, not only the positive ratio on lung adenocarcinoma is 40 to 50% but also they are detected in other tissue type of lung carcinoma, benign lung diseases and other organ cancers including colon cancer, stomach cancer and breast cancer. On the other hand, Maimonis P. et al. (Cancer Res., 50, 6738 (1990)) have reported a monoclonal antibody DF-L1 obtained using a lung adenocarcinoma tissue as the immunogen. However, the antigen which is detected using this antibody is present in sera of patients of not only lung adenocarcinoma but also squamous cell carcinoma, breast cancer and the like.
Thus, the monoclonal antibodies so far developed can hardly be regarded as diagnostic means specific for lung adenocarcinoma and are nor sufficient for screening, definite diagnosis and monitoring of metastasis, recidivation. In addition, lung cancers have different properties in terms of cell proliferation, development and the like, due to different tissue type of each lung cancer. Because of this, the corresponding therapeutic method varies depending on each tissue type. In consequence, it is extremely important to find an antigen and an antibody peculiar to lung adenocarcinoma for the diagnosis of lung adenocarcinoma, and furthermore, for the treatment of lung adenocarcinoma.